New research supports controversial idea that certain genes evolved to combat specific bacteria

New research reveals a mutation on a gene that makes children susceptible to a severe form of mycobacterial disease. The work not only supports a controversial idea that certain genes evolved to combat specific bacteria but also reveals new mechanistic details of how the immune system fights off one of the planet’s fiercest pathogens.

Led by Jean-Laurent Casanova, head of the Laboratory of Human Genetics of Infectious Diseases, the work lends further support not only to the controversial idea that an error in a single gene is enough to dramatically alter an individual’s risk for bacterial disease, but also to the notion that humans have sets of genes that are pathogen-specific.

“It’s incredible,” says Stephanie Boisson-Dupuis, a research associate in the lab. “In the past 10 years, the way that we think about the genetics of infectious disease has been redefined. Instead of just targeting the bacteria, we can now also target the immune system, and try to patch the holes that allow the bacteria to slip through.”

The mutation disrupts a gene known as IFN-γR1, which is charged with making a receptor for interferon γ, a molecule that directs immune cells to organize an attack. When the receptor is absent or rejects the molecule, it disrupts an immune system pathway that specifically targets mycobacteria.